The present invention relates generally to rotary selection devices and, more particularly, to a rotating indexing apparatus with positive positioning.
Indexing detent assemblies are found in a plurality of applications and are commonly used in rotary electronic switches. In such switches, considerable force frequently is needed to rotate the assembly. Detents commonly are engaged through use of bearings spring-mounted in a race configuration. Friction of the bearing assembly against the race frequently allows a selection shaft to stick between detents, where it fails to make an electrical connection. It would be desirable to provide a rotary detent indexing assembly that cannot be inadvertently left between detent positions. It also would be desirable to provide an indexing assembly in which friction is minimized.
In one preferred form, the present invention provides a rotary indexing apparatus for precisely positioning an external component secured thereto. The apparatus includes a race ring having a circumferential race surface facing inwardly toward an axial center of the race ring. The race surface includes a plurality of alternating hills and valleys, each valley configured to correspond to a detent position selectable by a user. The indexing apparatus also includes a selection shaft aligned with the axial center of the race ring. A detent wheel positioned on the selection shaft is rotatable within the ring by the user via the selection shaft. The detent wheel includes two spring loaded race wheels mounted in two substantially opposed recesses of the detent wheel, and two axles movably mounted within the recesses and upon which the race wheels are mounted. The race wheels are configured to roll along the race surface while the shaft is being rotated and to roll into valleys upon a halting of the rotation.
The above-described apparatus facilitates positive positioning of the selection shaft, and friction is reduced between the wheels and the race surface. The apparatus tends toward positive engagement in a detent, yet can be moved easily from one detent position to another. Implementing the above rotary indexing apparatus allows assembly time to be reduced and also eliminates or reduces need for replacement due to component failure. Utilizing the apparatus can make operation of operator-controlled devices more reliable and can lower maintenance costs.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.